1. Field of the Invention
The present invention relates to the art of electrochemical cells, and more particularly, a novel anode electrical lead. Moreover, the current invention provides an electrical path for an implantable battery by positioning the anode lead between the battery case and the lid and welding the battery lid to the case creating a hermetically sealed battery. The new process is simpler, requiring fewer steps and saves manufacturing costs.
2. Prior Art
The recent rapid development in small-sized electronic devices having various shape and size requirements requires comparably small-sized electrochemical cells of different designs that can be easily manufactured and used in these electronic devices. Preferably the electrochemical cell has a high energy density, and one commonly used cell configuration is a prismatic, case-negative cell design having an intermediate cathode flanked by opposed anode plates in contact with the casing and in electrical association with the cathode. In conjunction with smaller size batteries, enhanced characteristics such as nesting a lead from the anode collector between the wall of the battery case and the lid, creating a battery case negative design, is a unique novel way to increase the applicability of these cells to a larger number of situations. The prior art does not disclose such a connection.
For example, turning now to the prior art patents, U.S. Pat. No. 4,663,248 to Klein et al. discloses a cell having spirally wound electrodes in which an extension of one of the electrodes is caught and compressively held between the inwardly curled end of the container wall. The patent specifies that the invention requires the container end be curled inwardly to effect the requisite terminal connection. This is not the case in the current development.
Also, U.S. Pat. No. 4,873,160 to Miyazaki et al. discloses a battery with a lead captured between the case and the cover plate. However, the case is of insulating material unlike the cell of the current development.
Again, U.S. Pat. No. 1,971,275 to Rock discloses a negative battery terminal strip soldered to the zinc can below the upper end of the battery. The strip has a portion is connected to the terminal post. The lead external to the battery casing diminishes the applicability of the invention to various situations, in contrast to the invention which is disclosed in this application which increases the applicability of battery designs heretofore unrealized.
Finally, U.S. Pat. No. 5,955,217 to Van Lerberghe discloses a flat battery in which electrodes have portions extending between a cover foil and conductive frame parts. In this invention, there is no disclosure of removing excess lead or any welding, which is contrary to the teachings of the current invention. These untrimmed extensions and the like create cumbersome arrangements which are hard to use in various applications.
Thus, it can be seen, based on the disclosed prior art, that there is a need to develop a new anode electrode termination which will extend the applicability of the current electrochemical cells to new varieties of applications. The current invention advances technology and reduces manufacturing costs and fills many of the needs hereinbefore left unfilled.
The present invention provides a new battery design for attaching at least one anode lead to a battery case, creating a case negative design. The anode lead is nested between the case and the lid and the excess lead above the surface of the lid is ground or cut off and the case to lid seal is achieved by laser/electron beam welding. The new procedure enhances the hermicity of the cell and the new process is applicable to a number of additional applications. These include primary lithium batteries, implantable batteries, lithium based rechargeable cells, and also acid or alkaline based batteries.
The foregoing and additional advantages and characterizing features of the present invention will become clearly apparent upon a reading of the following detailed description together with the included drawings.